The present invention relates to a metering pallet for bag-like large receptacles, enabling free-flowing bulk material to be removed in a metered manner from the receptacle and enabling the pallet and receptacle to be transported after partial withdrawal and temporarily stored.
It is known to sell free-flowing bulk materials in bag-like large receptacles, usually called bigbags. Bigbags are normally stored on pallets and transported by floor conveyors, particularly fork-lift trucks.
Bigbags with a volume of about 100 liters to 3,000 liters, usually 500 to 2,000 liters, comprise one or more layers of a wide variety of materials, particularly fabrics of synthetic or natural fibers or tapes and sheets; frequently an innerliner of sheet material, e.g. polyolefin, is combined with an outer bag made of tape fabric. In the upper region, the bigbags have a closable filling opening, which is also used for ventilation during emptying, and normally have a number of carrying loops for use with hoists. At the bottom there is usually a bag outlet which when filled is tightened and tied or sewn together with one or more cords.
When bigbags are emptied, they are brought by hoists over the container to be filled. The outlet is opened, e.g. by releasing the closing cords, and the bag empties in an uncontrolled manner. Special devices have been constructed for dust-free emptying of bigbags containing inserted innerliners, but these devices cannot be used for metering or partial withdrawal.
Known devices for metering bulk goods from bigbags comprise a frame for holding the bigbag and a metering machine, the frame and machine together constituting the weight-carrying part of a weighing and metering station. A fork-lift truck or hoist places a bigbag on the weighing and metering station; after the bigbag closure has been opened, the front chamber of the metering machine fills with bulk material, so that a metering screw, in accordance with the preset metering parameters, and optionally a loosening device can be connected and bulk material can be discharged by gravity. These devices can be used for metering, but a partly-emptied bigbag cannot be removed from the receiving frame and transported to another place for temporary storage, without material running out and being wasted and the metering station needing to be cleaned.
Metered partial withdrawal and temporary storage in a reserve store are important particularly in enterprises where multi-component mixtures, including mixtures containing individual substances in small quantities, have to be kept in readiness, but where raw materials have to be brought in bigbags to meet quality, cost and environmental requirements. In enterprises using a large number of bulk materials and/or with frequent changes of product, furthermore, it is impossible for cost and space reasons to install a separate metering and weighing station for every product delivered in bigbags.